1. Field of the Invention
The invention relates to a switching system for transferring data between central units and controlled units. The system is applicable to telephone, telegraph, remote control, or, other data-processing installations employing at least two central data processing units having common access to various controlled units. In particular, means are provided to route signals through a second central unit to peripheral equipment when a first central unit cannot reach a peripheral unit directly.
2. Description of the Prior Art
In such installations there are provided, between the central units and the controlled units, peripheral units receiving orders from the central units and retransmitting them to the controlled units. The presence of the peripheral units is justified by the large number of controlled units and by requirements for adaptation of the speeds of the operation. The controlled units are divided into groups and each central unit has access to each group through a peripheral unit proper to it.
It is possible in such systems for a peripheral unit to fail and prevent the central unit -- to which it is linked -- from transmitting order to the corresponding group of controlled units and this will prevent calls, put through with the help of this central unit, from reaching their destination.